1. Field of the Invention
The present invention relates to a pad spring for disc brakes and a manufacturing method thereof and, more particularly, to a pad spring for disc brakes wherein the surface of the pad spring is roughened through the use of a sanding device using a basket, thereby increasing adhesive force of a coating material coated on the pad spring, and a manufacturing method thereof.
2. Description of the Related Art
Generally, a disc brake is a device that forcibly pushes frictional pads to opposite sides of a disc rotated together with each wheel of a vehicle in tight contact to brake and decelerate the vehicle using such frictional force.
The disc brake includes a caliper housing having a piston mounted therein, the piston being advanced and retreated in the caliper housing by braking hydraulic pressure, a carrier fixed to a vehicle body, a pair of pad plates having frictional pads attached to facing insides thereof being installed at the carrier, and a disc disposed such that a portion of the outer circumferential edge of the disc is inserted between the pad plates, the disc rotating together with each wheel.
The piston is disposed at the rear of the caliper housing to push the outside of one pad plate toward the disc. Fingers to surround the outside of the other pad plate are formed at the front part of the caliper housing opposite to the piston.
When the piston is operated such that one pad plate pushes one side of the disc, therefore, the other pad plate pushes the other side of the disc while being led by the fingers with the result that the disc is caught between the frictional pads.
The carrier is fixed to a knuckle of the vehicle body by bolts. The respective pad plates are slidably disposed in the carrier. Between the pad plates and the carrier are provided pad springs to guide sliding of the pad plates and to restrain shaking of the pad plates. Each pad spring is manufactured by pressing and bending a stainless steel sheet or a spring steel sheet.
In the conventional disc brake with the above-stated construction, however, the pad plates, which are made of a metal material, directly contact the pad springs, which are also made of a metal material, during sliding of the pad plates to push the disc with the result that loud noise may be generated or smooth sliding of the pad plates may be disturbed due to friction between the pad plates and the pad springs.
Meanwhile, a method of coating a pad spring for vehicle disc brakes that is capable of coating the inside of the pad spring with Teflon is disclosed in Korean Registered Patent Publication No. 10-668978 (published on Dec. 28, 2005).
In the conventional method of coating the pad spring for vehicle disc brakes, proper coating is not performed with the result that a coated region is poor and has many defects. In addition, coating time is long.